CENSUS DATA: DOWNLOADING AND USING IN ARCMAP

2/13/2008 GEOSPATIAL RESOURCES AND MAP COLLECTION CENSUS DATA: DOWNLOADING AND USING IN ARCMAP Downloading Census boundary files and accompanying ...
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2/13/2008

GEOSPATIAL RESOURCES AND MAP COLLECTION

CENSUS DATA: DOWNLOADING AND USING IN ARCMAP

Downloading Census boundary files and accompanying Census attribute tables are both common tasks in GIS. The following tutorial will guide you step by step how to download and join together these two data sources. * This tutorial is for users who are familiar with ESRI’s ArcMap software. * This tutorial will take approximately 1 hour to complete.

Downloading the Census Tiger/Line File 1. Go to ESRI’s Geography Network (www.geographynetwork.com). 2. On the upper right hand corner of the screen click on Free Resources. 3. Choose Census TIGER/Line 2000 Data (see illustration below) .

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4. On the left column of the Census 2000 TIGER/Line Data page Choose Preview and Download. 5. Select Indiana as the state and click Submit Selection. 6. Under Select by County choose Delaware. 7. In the following screen choose Block Groups 2000 and click on Proceed to Download. (see illustration below)

*If you scroll down to the bottom of the screen you will see that you can also download the census block demographics SF1 table from this site. This is an easy way to download the geography boundary shapefile and the accompanying attribute data all at once. But in this tutorial we are looking to download information from the SF3 table, so we must download from the US Census Bureau’s FactFinder website instead. 8. Read the information and press Download File. 9. Save the file to your personal folder and give it name that is descriptive of what the data shows, such as Delaware_BlkGrps. (Just make sure that you keep the .zip extension). 10. Unzip the dataset after download. 11. The unzipped file contains another zipped file – unzip this one also. 12. Open up this shapefile in ArcMap.

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*You will notice that shapefiles from TIGER/Line come in decimal degrees. You can choose to re-project them into the coordinate system that best fits your needs if you like. For this tutorial we are not going to re-project the shapefile. *You will also notice if you view the files attribute table that no actual census demographic information is attached other than fields identifying the geography. That brings us to our next step:

Downloading Census Attribute Data from American FactFinder This part of the tutorial will show you how to download census attribute data from the US Census Bureau’s website called American FactFinder. 1. Open your web browser and navigate to www.census.gov 2. Click on the American FactFinder link on the left side of the page. 3. Once on the FactFinder page click on Data Sets on the left hand menu. (see illustration below)

4. Under the Census 2000 tab choose Census 2000 Summary File3 (SF 3) Sample Data and select Detailed Tables in the menu to the right. (see illustration below) Ball State University Libraries Geospatial Resources and Map Collection www.bsu.edu/library/collections/gcmc

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*2000 Summery File 3 contains data from the 2000 sample census and is used to diagram information about education, family status and education. 5. Choose the geo within geo tab and input the following: a. Show me all: Block Groups b. Within: county c. Select a State: Indiana d. Select a County: Delaware e. Select one or more geographic areas: All Block Groups 6. Click the Add button. (see illustration below)

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7. Click the next button. 8. Under the show all tables tab add the following table a. P52. Household Income in 1999 then click Add. 9. After selecting these tables click on the show result button. 10. Click on the print/download button at the top of the screen and download the data. 11. In the Detailed Tables Download window scroll down the page and find the Heading Database Compatible (data rows only) and choose Microsoft Excel (.xls). (see illustration below)

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12. Click the OK. 13. Save this folder in the same place you saved the TIGER/Line files earlier in this tutorial. 14. Unzip the contents of the downloaded folder.

*Now that the census data has been downloaded there is still some prep work to do before it can be joined to your census block group shapefile in ArcMap, which brings us to our next step in the tutorial:

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Opening the Census File in Excel and Converting it to a Database File Compatible with ArcGIS 1. Browse to the folder where you unzipped the census data. Open the downloaded table (dt_dec_2000_sf3_u_data1.xls) with Microsoft Excel. Note: there will be two .xls files; you want to open the one with the word “data” in its name.

*The second row of the table is the descriptive name of the columns. Unfortunately, these name formats aren’t compatible with the type of file that ArcMap uses. We will have to delete this row from the table. But first, we may want to rename the columns in row one to a more descriptive title. Just remember the title can’t be over 10 characters long and there can’t be any underscores, hyphens, spaces or any other nontraditional characters. Example: P001001 could be called TotPop. 2. Once you have renamed the titles in Row 1 Right-Click on the number 2 on the left hand of row two and choose Delete to remove the row of descriptive names. (see illustration below)

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3. Save your changes to the document and Close Excel.

Joining the Census Boundary Files to the Excel Table Now that we have downloaded the census data we can go back to the ArcMap document that we opened earlier and join our data to the Delaware County Block Groups shapefile. 1. Click on the Add Data button and browse to the census data excel file that you saved.

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2. Double-click on the excel file in the open window to browse into it and then choose “Sheet0$” and click Add.

3. Right_Click on the census block geography layer and select Joins and Relates> Join.

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4. In the Join Data Dialog, set the following: a. Join attributes from a table b. Based on: STFID c. Table to join: Sheet0$ d. Field to base the join on: GEO_ID2.

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5. Click OK. 6. Open the attribute table for the Census Block Geography layer to make the sure the join was successful. 7. Close the attribute table. 8. Right-Click on the Census Block Geography layer and go to Data> Export Data.

9. If you have set your data frame to a specific coordinate system then choose the data frame under Use the Same Coordinate System as: if not, then choose this layer’s data source. 10. Browse to the folder where you saved the original shapefile and excel documents and save it as Delaware_Population.shp

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11. In the window that pops up choose Yes to add the exported data to the map as a layer. 12. Remove the Census Block geography layer from ArcMap. 13. Remove the excel table you added. 14. Right-Click on the Delaware_Population and open its attribute table to confirm that the census information is included in this shapefiles attributes.

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15. Save the map document. You have now downloaded and joined both a census geographic boundary Tiger/Line shapefile and the accompanying census data table from American FactFinder. You can now symbolize the data to best represent what your map is showing.

Please complete this tutorial by filling out the user feedback form found at:

http://www.bsu.edu/libraries/forms/gismaptutorialfeedback.php

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